Top defense officials of South Korea, Japan, Australia and New Zealand are set to hold a rare meeting on the occasion of this week's defense ministerial meeting of the North Atlantic Treaty Organization (NATO), sources said Monday.The gathering comes as the four Indo-Pacific partners of NATO, dubbed the IP4, join the NATO defense ministerial meeting for the first time on Thursday and Friday.In the meeting proposed by Australia, the defense officials are expected to discuss ways to strengthen cooperation with NATO, the sources said, in the face of deepening military cooperation between North Korea and Russia.From South Korea, Vice Minister Kim Seon-ho is set to attend the meeting on behalf of Defense Minister Kim Yong-hyun, considering the parliamentary audit schedule.The IP4 members adopted a joint statement denouncing the deepening military ties between Russia and North Korea and agreed to step up cooperation during a NATO summit held in Washington in July.In a press conference earlier this month, NATO Secretary General Mark Rutte announced the IP4's attendance for the upcoming meeting and said he looks forward to "forging a shared approach to shared challenges" with the Indo-Pacific partners.Source: Yonhap News Agency